Screening apparatus



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Sept. 25, 1962 0 P. AUBERT-MAGUERO SCREENING APPARATUS Filed July 22, 1958 United States Patent 3,055,500 SCREENING APPARATUS Paul Aubert-Maguero, 8 Rue Camille Flammarion, I'erigueux, Dordogue, France Filed July 22, 1958, Ser. No. 750,198 Claims priority, application France July 24, 1957 4 Claims. (Cl. 209-288) This invention relates to screening apparatus of the type comprising a cylindrical cage structure rotatable about a horizontal axis, wherein the longitudinal bars of the cage structure, which bars provide the screening means, are so arranged that the gaps between adjacent bars are variable, and the gaps are narrower when the bars are positioned in the lower portion of the cylinder, than when the bars are positioned in the upper part of the cylinder, \so that any material or articles to be screened that may have become jammed between an adjacent pair of bars when such pair was positioned at a lower position, will drop back into the inner space of the structure as the said pair of bars spread apart on rising to the upper part of the cylinder.

This invention has as an object the provision of screening apparatus of the type just specified, which will be more reliable and eflicient in operation than previously known devices, and the invention is especially concerned with the construction of the means for varying the gaps between the screening bars.

An embodiment of the invention will now be described for purposes of illustration but not of limitation with reference to the accompanying drawings, wherein:

FIG. '1 is a diagrammatic view illustrating the cross sectional configuration of the screen bars;

FIG. 2 is an end view of an embodiment of the improved apparatus; and

FIG. 3 is a section on line 3-3 of FIG. 2.

As shown in FIG. 1, the longitudinal bars of the cylindrical cage structure comprise fixed and movable bars. A fixed bar such as has a cross sectional shape which increases in width away from the axis of the cylindrical cage. 'In the illustrated construction, the cross section of bar 10 has a longitudinal axis of symmetry 11 extending through the cage axis and is defined by two sides 12 and 13 diverging away from said cage axis interconnected by a pair of arcs 14 and 15, with the chord subtending the are -14 nearer the cage axis being smaller than the chord subtending the outer are 15. The arcs 14 and 15 may be circumferential arcs each extending over about 180. 7

The movable bars such as 16 are generally elliptical or oval in cross sectional shape.

Referring now to FIGS. -2 and 3 an embodiment of improved screening apparatus according to this invention is shown comprising fixed and movable bars of the general form just described with reference to FIG. 1, although it should be understood that the teachings of the invention would also be applicable to apparatus of the same general type wherein the bars have different configurations from those shown in FIG. 1. The end of the apparatus which is not shown in FIGS. 2 and 3 is similar to the illustrated end except that it requires no control apparatus. Herein a movable bar .16, of elliptical cross section, has a pivot 21 projecting axially therefrom for rotatably mounting the bar in a flange 22 which defines an inner circle through which the articles to be screened are loaded. Secured to the pivot 21 is a crank or lever 23 having a roller 24 journalled on its outer end for cooperation with a camway 25. The camway is secured on the stationary frame of the apparatus of course by its side not confronting the levers 23 for avoiding interference therewith and extends over substantially the upper half thereof. The camway includes two end portions 26 and 27 of gradually increasing and decreasing radius respectively, as considered in the direction of rotation of the cage indicated by the arrow 1. Each lever 23 is acted on by a torsion spring 28 in a direction to urge the related roller 24 against the camway 25. Mounted for slidable adjustment on flange 22 is an annular flange 29 carrying projecting studs or pins 30 arranged generally in radial alignment with the respective levers 23, although their exact position relative to the levers is adjustable as will be later described. The annular flange 29 is guided by a plurality of arcuate segmental plates 31 and means are provided, such as bolts 32, for releasably urging the plates 31 against the flange 22. The annular flange 29 is formed on its inner periphery with gear teeth 33 and the flange 22 is formed with a hole 34 into which the extremity 35 of a suitable key 36 may be inserted, carrying a pinion 37 and on its other end a handwheel 38. Bars 10 are fixed on flange 22. Operation is as follows:

During rotation of the cage or drum structure, as a movable bar 16 is positioned in the top portion of the structure, the roller 24 pivoted on the lever 23 associated with said bar cooperates with the camway 25 so that the bar is so positioned that the major axis'of the ellipse comprising the cross section thereof is directed towards the center of rotation, so that the gap defined between said bar and the adjacent fixed bars 10 is a maximum, and permits ready release of any article lodged between said movable bar and an adjacent fixed bar. As the cage continues to rotate the movable bar 16 approaches the outlet end 27 of the camway 25 and is caused to rotate about its pivot 21 due to the fact that the spring 28 applies the associated follower roller 24 against the camway 25 which has a decreasing radius. The bar 16 gradually moves away from its radial position and assumes a transverse position as shown in the lower part of FIG 2, wherein said bar defines with the adjacent fixed bars a gap of minimum width corresponding to the desired screening dimension. This screening position of the movable bar is positively determined by abutment of lever 23 against the adjacent pin 30. The movable bar after having travelled over the lower semi-circumference, is restored to its retracted position due to the cooperation of the follower roller with the camway 25.

For altering the adjustment of the screening gap or interval, the end 35- of the key 36 is inserted into the hole 34 so as to bring the pinion 37 into meshing engagement with the teeth 33 and thereafter the key is rotated to rotate the annular flange 29. The relative position between each pin 30 and the related lever 23 is thus altered, so that, by the action of spring 28, the abutting position of lever 23 against the pin 30 is correspondingly altered to provide a new adjusted screening gap.

What I claim is:

1. A screening apparatus comprising annular supporting means rotatably mounted about a horizontal axis, first longitudinal bars secured on said means having an elongated cross section directed towards said horizontal axis and disposed at regularly spaced angular intervals, second longitudinal bars alternating with the first said bars, disposed at regularly spaced angular intervals and pivotally mounted in said annular supporting means about axes parallel to said horizontal axis of rotation, a crank rigid with each of said second longitudinal bars, an annular plate adjacent said annular supporting means, co-axial thereto and including studs disposed at regularly spaced angular positions, said studs projecting into the path of said cranks, means for adjusting the angular position of said annular plate with respect to said annular supporting means, cam and spring means co-acti-ng with said 3 cranks for maintaining the second said bars in a position wherein their longitudinal axis is substantially directed towards said horizontal axis of rotation when the second said bars are above said horizontal axis, said spring means being also operative for causing said cranks to contact the corresponding studs when the second said bars are below said horizontal axis and when their cranks are disassociated from said cams.

2. A screening apparatus comprising, at regularly spaced angular intervals on the surface of a cylinder rotating about a horizontal axis, a plurality of fixed elements each having a cross section convergent towards said axis, a plurality of pivotable elements on said cylinder surface which are interposed between said fixed elements, each of said pivotable elements forming with the adjacent fixed elements screening intervals, annular plates disposed at the ends of said fixed and pivotable elements, said annular plates and fixed elements being rigidly interconnected, and means for rotatably mounting said pivotable elements on said annular plates about axes parallel to that of said cylindrical surface; said apparatus further comprising means for pivoting said pivotable elements in relation to said annular plates whereby said intervals formed between said pivotable elements and the adjacent fixed elements have a minimum width when said pivotable elements are underneath said horizontal axis during the rotation of said cylinder, and have a maximum width when said pivotable elements are above said horizontal axis during said rotation.

3. An apparatus as set forth in claim 2, wherein said means for controlling the pivotal motion of said pivotable elements comprise spring means each associated with a separate pivotable element and fixed cam means common to all of said pivotable elements and stop means limiting for each pivotable element the pivotal movement thereof under the influence of the spring means associated therewith.

4. An apparatus as set forth in claim 2, wherein said means for controlling the pivotal motion of said pivotable elements comprise spring means each associated with a separate pivotable element and stationary cam means common to all of said pivotable elements, stop means limiting for each pivotable element the pivotal movement thereof under the influence of the spring means associated therewith, and further means for causing the angular shift of said stop means in relation to said annular plates thereby causing the intervals between the first said element and second said elements to be controlled.

References Cited in the file of this patent UNITED STATES PATENTS 1,196,975 Pease Sept. 5, 1916 FOREIGN PATENTS 957,651 Germany Feb. 7, 1957 1,085,675 France Feb. 4, 1955 

